Russia has threatened to target US-led coalition aircraft flying over Syria in a sign of the mounting tensions in the region after an American fighter jet downed a Syrian government warplane.
The Russian defence ministry said it was also pulling out of an agreement with the US intended to avoid mid-air clashes over Syria. Taken together, the moves underline how the Syrian war is threatening to become a flashpoint for a broader international conflict.
The US and Russian escalation came as Iran launched a ballistic missile at Isis targets in Syria, underlining the extent to which Tehran, Moscow and Washington are all ramping up efforts to shape the six-year civil war.